Most high-order, harmonic-generation experiments to date have used gas target pressures in excess of 10 Torr. These high pressures have been used to enhance the harmonic signal, which increases quadratically with the pressure. The phase-mismatch factors (caused by both neutral and ionized media) increase with the pressure as does the effect of refraction of the incident laser when the medium be...

In scattering theory the far field pattern describes the directional dependence of a time-harmonic wave scattered by an obstacle or inhomogeneous medium, when observed sufficiently far away from these objects. Considering plane wave excitations, the far field pattern can be written as a function of two variables, namely the direction of propagation of the incident plane wave and the observation...

This paper proposes a method for constructing an experimental power beam pattern (PB) of RATAN-600 based on the sample of NVSS sources observed in the process of a deep sky survey near local zenith. The data obtained from observations of radio sources at λ7.6 cm in nine bands of the survey (the 2002 and 2003 sets) are used to construct vertical PB of the telescope at rather large offsets from t...

A spherical acoustic wave is scattered by a bounded obstacle. A generalization of the ‘optical theorem’ (which relates the scattering cross-section to the far-field pattern in the forward direction for an incident plane wave) is proved. For a spherical scatterer, lowfrequency results are obtained by approximating the known exact solution (separation of variables). In particular, a closed-form a...

Recently, mobile communication systems are suffering from exponentially increasing data traffic. As a promising solution to the increase in data traffic, a coordinated multi-point transmission and reception (CoMP) scheme has been proposed. Although a great deal of research has been done on this new technology, the performance of mobile communication systems with CoMP has not been evaluated prop...

Abstract: This contribution presents a new approach for analysing spatial directions in room impulse responses captured with source and receiver of adjustable directivity. A distinct peak in a room impulse response is usually associated with an acoustic path length of direct or reflected sound. Given the ability to modify the directivity of source and receiver by spherical beamforming, beam coe...

In this study, a compact semi-circular metamaterial-inspired dual-band antenna is presented. The total antenna size is 0.22 o × 0.19 o × 0.02 o. Simulation results show dual-band operation with an impedance bandwidth of 2.7% for first band (resonant at 4.1 GHz) and 25.7% for second band (resonant at 6.15 GHz). The proposed compact metamaterialinspired antenna shows monopole-like radiation patte...

Reliable measures of speaker positions are needed for computational perception of human activities taking place in a smart-room environment. In this work, we investigate the effect of talkers head orientation on the accuracy of acoustical source localization techniques and its relation with the talker directivity pattern and room reverberation. Two different representative speaker localization ...

Based on the free precession model of the isolated pulsar PSR B1828-11, Link & Epstein (2001) showed that the observed pulse durations require the radio beam to have a non-standard shape: the beam duration is larger for beam sweeps farthest from the dipole axis. In their analysis they assumed that the actual precession period is ≃ 500 d. Recent theoretical studies suggested that the actual prec...